Topic 2: Biological Molecules

Question 1

What is the general formula for monosaccharides?

Answer 1

(CH2O)n

Question 2

What direction is the first hydroxyl group in alpha glucose?

Answer 2

Down

Question 3

What direction is the first hydroxyl group in beta glucose?

Answer 3

Up

Question 4

What bond is formed in the condensation reaction of two alpha glucose molecules?

Answer 4

alpha 1-4 glycosidic bond

Question 5

What bond is formed in the condensation reaction of two beta glucose molecules?

Answer 5

Beta 1-2 glycosidic bond

Question 6

Name 3 disaccharides

Answer 6

Maltose, Sucrose, Lactose

Question 7

What type of reaction makes disaccharides?

Answer 7

Condensation

Question 8

What two things form starch?

Answer 8

Amylose and Amylopectin

Question 9

List the differences between amylopectin and amylose

Answer 9

• amylose is a helix
• amylopectin is branched
• amylopectin has alpha 1-6 branches
• amylopectin is hydrolysed/broken down quicker

Question 10

True or False? Glycogen is similar to amylose

Answer 10

False it is branched so is similar to amylopectin

Question 11

Benefit of glycogens structure?

Answer 11

It is heavily branched so can be very easily hydrolysed for energy

Question 12

What is cellulose made up of?

Answer 12

poly (1-4) beta glucose

Question 13

Describe the structure of cellulose

Answer 13

A chain of B glucose, every alternate glucose is inverted, linked by hydrogen bonds forming cellulose microfibrils

Question 14

Benefit of inverted Beta glucose in cellulose?

Answer 14

maximises number of hydrogen bonds making it stronger

Question 15

Why do unsaturated lipids have a lower melting point?

Answer 15

weaker intermolecular forces made by the double bonds

Question 16

What makes up a triglyceride?

Answer 16

glycerol and 3 fatty acids

Question 17

What are triglycerides used for and why?

Answer 17

They are non-polar so used for storage, insulation and protection

Question 18

What are phospholipids made of?

Answer 18

2 fatty acid chains, glycerol, phosphate head

Question 19

What is formed when a phospholipid chain enters water?

Answer 19

A micelle

Question 20

What are proteins made up of?

Answer 20

Amino acids

Question 21

What bond holds polypeptides together?

Answer 21

Peptide bond

Question 22

What is primary structure?

Answer 22

The amino acid sequence

Question 23

What is secondary structure?

Answer 23

Folding of polypeptide to form alpha helices and beta pleated sheets

Question 24

What is tertiary structure?

Answer 24

Further folding held by hydrogen, ionic and disulphide bonds. making a protein globular or fibrous

Question 25

What is quaternary structure?

Answer 25

2 or more polypeptide chains held together

Question 26

Give the features of haemoglobin

Answer 26

- conjugated globular protein with all levels of protein structure - 4 globins with polar and non-polar R groups - 4 haem groups - 4 O2 molecules - compact globular protein

Question 27

What is the purpose of haemoglobin?

Answer 27

To bind loosely and reversibly to O2 molecules to transport it in blood forming oxyhaemoglobin

Question 28

What is the order of structure in collagen?

Answer 28

molecule - fibril - fibre

Question 29

Give 4 properties of collagen

Answer 29

- fibrous protein - high tensile strength - insoluble - flexible

Question 30

What is a collagen molecule made up of?

Answer 30

Alpha chains in elongated helices creating a triple helix

Question 31

How are collagen helices bonded to make fibrils?

Answer 31

Covalently cross linked

Question 32

Why are collagen fibrils lined out in a staggered way?

Answer 32

To make sure there are no areas of weakness

Question 33

Give 5 properties of water

Answer 33

- solvent - specific heat capacity - latent heat of vaporisation/fusion - denser as a liquid - cohesive forces - adhesive forces - a source of protons - salts ionise when dissolved in water

Question 34

What is the specific heat capacity of water?

Answer 34

4.2J per gram per degree

Question 35

What feature of water helps surface tension?

Answer 35

Cohesive forces

Question 36

What feature of water helps transpiration?

Answer 36

Adhesive forces

Question 37

Why does the latent heat of vaporisation help animals?

Answer 37

As water in the body evaporates as sweat the animal is cooled down as the evaporation removes the hot water from the body